In different industries, e.g. manufacturing industry, robots have been used for decades. Specifically, robots have been a useful tool in order to automate processes and thus increase both productivity and efficiency. Known robots can have an arm connected to a body, which arm is moved in accordance with a preset program. The arm can hold a tool designed to carry out a desired work or process, e.g. welding of a material. Tools connected to a robot arm usually operate by use electricity or some other source of power, e.g. pressurized air. The power can be provided to the tool via a cable along the arm. Different cables and hoses are also needed for other purposes, and therefore a whole package of cabling, often called dress package, is normally drawn along the robot arms, from the base or foot of the robot to the end of the upper arm, to the wrist and the tool.
The end part of a robot arm according to prior art is provided with a wrist. The wrist is provided with a process turning disc and a tool is mounted on the process turning disc. The wrist is provided with a motor, and the output shaft of the motor rotates the process turning disc and the tool about a centre axis, which also extends through the wrist. The type of tool that is mounted on the wrist is decided by the customer. The wrist is also rotatable/tiltable about another centre axis that is perpendicular to the mentioned centre axis.
Commonly, the cable along the arm is attached to the arm at points spaced apart from each other, and further on to the wrist and the tool. The cable is arranged in a non-stretched manner between the points, which enables the arm to have a fairly high range of free movement without being limited by the cable. A cable as above is exposed to wear, mainly due to friction against different parts of the arm. This results in that the cable has to be changed and replaced after a period of use.